Here is a quick idea for a simple 6c19p SE design.
- Operating point at 210V at 45 mA with -80V at grid.
- Say 300V at B+
- Swing from -5V @ 40V @ 70mA to -160V @ 380V @ 25mA.
- Loadline at 5k or 7k5 both have similar outcome.
- Require a grid signal of around 50Vrms to drive to full power, with a bit of headroom to avoid A2 operation.
- Assuming 2Vrms input, require a driver stage with a gain of around 25 minimum.
- CSS loaded input stage could use C3g, 6n6p, 6DJ8/family, 6/12SN7, etc, a lot of tube choices in the medium mu grouping. Given the B+ of around 300V, operating the input tube at around 200V would be ideal.
- Normal cathode biasing and capacitor coupling.
The great thing is that I have most of the parts lying around, with the exception of the power transformer. This can make good use of the Lundahl choke rated at 150mA, the CSS kit from K and K Audio and a few Jensen and Cerafine electrolytic capacitors. As usual, my enemy is time in getting around to hooking it all up. This would make a nice stereo amp. Maybe a schematic to follow.
This could even work for swapping out the output tube for a 45, by changing the bias capacitor and heater supplies. With B+ at 300V, the 45 could be 250V at 50V bias. Could work as a great convertible experimenter's amp.